Gear pump with flow cushioning means



Feb. 1, 1949. e. w, MULLER 1 2,460,649

GEAR PUMP WITH FLOW CUSHIONING MEANS Original Filed March 7. 1942 2 Sheets-Sheet 1 Q R Q t Q 7.3} n 0:

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I\ i i w INVENTOR. GEZA W MULLER AHarneu- 1949- Y G. w. MULLER. 2,460,649

GEAR PUMP WITH FLOW CUSHIONING MEANS Original Filed March 7, 1942 2 Sheets-Shed 2 IN VEN TOR.

pfiszA W MULLEK BY AHor-ne q Patented Feb. 1, 1949 GEAR PUMP WITH FLOW CUSHIONING MEAN S Geza W. Muller, Bron, France; vested in the Attorney General of the United States Original application March 7, 1942', Serial No.

433,808. 27, 1945, mar! 20, 1941- Divided and this application August Serial No. 612,966. In France Feb- Section 1 Public Law 690, August 8, 1946 Patent expires February 20, 1961 I 2 Claims. (01. 103-126) I The present invention relates to gear pumps and more particularly to such gear pumps as are used industrially for displacing viscous fluids, for example fluids of this category employed for spinning artificial textile fllaments and threads, and as are generally interposed between a master pressure pump and the spinning dies, the ahief function of such gear pumps being to regulate the rate of delivery of the fluid.

An object of the invention is to provide for the aforesaid and like uses a gear pump having such an improved construction as to fulfli practical requirements under better conditions than similar pumps as used heretofore.

Another object of the invention is to provide an improved gear pump the structure of which is so devised as to cause the whole of the fluid flowing therethrough to perform during operation lubrication of at least some of the revoluable members of the pump and particularly of the gear shafts.

Another object of the invention is to provide a gear pump having such an improved structure as to damp away the fluid pulsations, thereby enhancing the steadiness in the rate of flow of the liquid and ensuring better spinning conditions when said liquid is used for the production of artificial textile filaments or threads.

A further object of the invention is to provide a gear pump of such improved construction as to enable the fluid to circulate therethrough directly without being hindered or throttled and without any whirling or stopping effect, thereby avoiding such sedimentations as might otherwise clog up the circuit or interfere with proper spinning conditions.

recesses for the gears and side plates delineating 4 and closing the pump body.

Figures 2 and 3 are elevational views showing the side plates.

. Figure 4 is a side view showing the body plate separately.

Figure 5 is a diagrammatic elevational view showing the body plate, the other parts being A still further object of the invention is to provide an improved gear pump of simple and rugged construction particularly well suited for the handling of viscous liquids used in the production of artificial textile filaments and threads and comprising self-contained means ensuring automatic flushing lubrication by the liquid itself and at the same time great regularity of flow.

With these and such other objects in view as will incidentally appear hereinafter, the invention comprises the novel construction, combination and arrangement of parts that will now be described with reference to the accompanying diagrammatic drawing exemplifying the same and forming a part of the present disclosure.

In the drawing:

Figure 1 is a vertical sectional view showing in its entirety an improved gear pump according to the invention comprising a body plate having omitted.

Figure 6 is a sectional view along the line X-X of Fig. 5.

Figure 7 is a sectional view of a modification of a detail of the pump.

Like reference characters designate like parts throughout the several views.

The constructional form of the invention illustrated in the drawing is a gear pump specially adapted for the handing of viscous liquids adapted to be spun into filaments or threads such for example as viscose, acetate, cupro-textile, artificial wool or the like.

Advantageously the pump body comprises a middle or body plate i formed with a pair of circular recesses 2 in which the gears 3 are snugly received. The middle plate 9 is closed and de- Communication between the suction duct 8 and the suction chamber l8 of the pump takes place through a duct ID, a chamber ll and a further duct l2. tween the delivery chamber IQ of the pump and the delivery duct 9 takes place through-ducts l3, l4 and I5.

The chamber l l is preferably formed in a separate front bracket I], while the duct [I is formed in a rear plate. l6, said bracket and plate being bolted or otherwise flxedly secured to the side plates 4, 5 and pump middle plate I.

As shown in Figs. 1 and 2, there is advantageously interposed on the delivery duct 9 intermediate the holes for the pins 6, 61a ring or washer 20 having an annular groove 2| communicationg with said duct 9. The ring or washer 20 may be axially bored to provide the duct 13 which communicates with the delivery chamber IQ of the pump and also with the duct H Likewise, communication be- The path of the liquid through the apparatus shown in the drawing is as shown by the arrows and may be described as follows:

The liquid sucked in by the pump enters the apparatus through the inlet aperture 22 and flows through the duct 8, then successively contacts or licks the front ends of the pins 6, 61

where they are journalled in the side plate 4. Thereafter the liquid enters the annular chamber H through the duct l and penetrates into the suction chamber l8 of the pump through the duct II. The liquid forced out of the delivery chamber i9 enters the duct l4 through the duct l3 bored in the ring 20 and then penetrates into the duct 9 through the duct l5. After contacting and flushing the part of the pin 61 journalled in the side plate and flowing through the groove 2| in the ring 20 (see Fig. 2) the liquid contacts or licks" the part of the pin 6 journalled in the side plate 5 and is discharged through the outlet aperture 23.

It will be seen that the whole of the liquid moved by the pump can thus contact or flush both ends of the gear-carrying pins 6, 61 where they are journalled in the side plates 5, 5.

The circulatory circuit which has iust been described presents amongst others the advantage of providing a through passage devoid of any throttling point and of giving rise to no whirling or stopping point where otherwise the liquid might settle down and build sediments which might choke proper flow and hinder suitable spinning operation.

Alternatively, the following constructional arrangements may be adopted:

The gears 3 may be so mounted or splined upon their operating pins 6, 61 as to "float upon them, the driving feathers 25 housed in said pins coacting with grooves 26 formed in the'bore of said gears 3 so that no axial thrust can be transmitted to these gears.

In order to provide for the required degree of liquid tightness on that side where the pin $1 is driven by the outer control shaft 21, elastic gasket 28 is provided so as to seal the chamber ii on the front side. As shown in Fig. 1, said'gasket comprises a U-shaped annulus and may be made for example of synthetic rubber.

Furthermore, owing to the fact that it contacts with the pumped fluid, said elastic gasket has the supplementary effect to damping the pulsations and toavoiding the irregularities of the rate of delivery of the pump.

In the constructional form shown, the gasket 28 is abutted against a washer 29 having a tight fit in a shouldered portion of the front bracket In order to improve said damping effect of the gasket 28, it is advantageous to provide the latter with grooves in one at least of the contact walls between said gasket and the washer 29. Preferably, these grooves having a suitable shape, for example a circular (grooves 281, Fig. 7) or radial shape, will be situated in the bottom wall of said gasket 28.

The shaft 21 which may be connected to the pin 61 in any approved way drives the latter advantageously as illustrated in Fig. 1 owing to co-action between grooves 30 in the rear end of said shaft and a key or cotter 3i set through the pin 61. The sectional area of the key or cotter 3| is preferably reckoned so that in case of jamming or of any abnormal resistance occurring in the pump operation, said key or cotter 3| should be sheared, thereby protecting the rest of the mechanism against any such undue stress as might otherwise seriously damage the most costly parts of the apparatus.

In accordance with another alternative feature of the invention, the shaft 21 is independently lubricated, for example by means of a lubricator 32 having a screw-threaded reduced shank engaged through a hole tapped in the bracket H, the extremity of said shank being in communication with a groove 33 in said shaft so as to hold the latter in proper longitudinal position.

Moreover, according to a particularly advantageous arrangement, the suction chamber l3 and delivery chamber i9 formed in the middle plate I are defined by walls extending askew and generated by the intersection of an oblique cylinder (as shown in chain lines in'Fig. 6) or a skew prism with the cylindrical recesses 2 in which the gears 3 are accommodated, the geometrical axis YY of said cylinder or prism being situated in the plane of tangence X-X of the pitch circles e of the gears 3 and passing through the point of contact 0 of the pitch circles located in the mean plane of said gears. The degree of slant of those edges which define the suction chamber I8 and the delivery chamber i9 with respect to the gear teeth should be preferably so selected as to cause the nicks of two consecutive teeth to be continuously in communication with said chambers l8, I9. The purpose of this arrangement is to regularize the rate of delivery of the pump.

According to a further alternative constructional form, regularity of the rate of delivery may be still further improved (this being of the utmost importance for spinning) by interposing either on the suction duct or preferably on the delivery duct of the pump a second resilient damping member such as a rubber pad or stopper 34 arranged in the end of the duct 9 and providing for the resilient material of which it is made an accurately bored recess 35. Said stopper 34 is fitted on a cap plate 36 fixed to the side plate 5 by means of a screw 31.

It will be seen that owing to the foregoing construction, the several objects of the invention are fulfilled inasmuch as it becomes possible by simple and cheapmanufacturing means to provide a self-lubricating gear pump using the pumped liquid as a lubricating medium and possessing great regularity of rate of liquid delivery, thereby ensuring a major advantage particularly where the pump is intended to feed liquid to spinning dies in the production of artificial textile materials.

This application is a division of pending application, Serial Number 433,808, filed March 7, 1942, now issued as Patent No. 2,386,257.

What is claimed is:

1. A gear pump comprising in combination a pump body, recesses in said body, pump gears housed in said recesses, a fluid circuit through said body comprising suction and delivery ducts on opposite sides of said gears, said delivery ducts being so shaped as to form at least one elbow having a leg extending toward said gears, said body having a bore therein forming an alined continuation of the end of the elbow leg remote from said gears and extending to the outer surface at said body, a plate shaped to conform to the outer body surface at said bore, a rubber stopper block carried by said plate and projecting into said alined bore so as to face the coming flow of said fluid whereby the pulsations of the fluid in the delivery duct are damped, and means for REFERENCES CITED securing said plate and rubber block in position with respect to said bore m'ghgf ialliigwgr'igelll'zterences are of record m the 2. A gear pump according to claim 1 wherein said securing means comprises a projection I NITED BTA'I'ES PATENTS formed on said plate and threadabiy mounted Numberv Name Date in said bore, and means for locking said plate 11,559 Pease Aug. 22 1854 and threaded projection against rotation. 2,318,128 Tabb May 1943 2,407,923 G GEZA w. MULLER. 10 Sept 4 

